Zero print suppression mechanism for printing calculators



Dec. 31, 1963 3,115,828

ZERO PRINT SUPPRESSION MECHANISM FOR PRINTING CALCULATORS R. D. MQOARTHUR Filed May 21, 1959 United States Patent 3,115,828 ZERO PRINT SUPPRESSIGN MECHANHSM FOR PRINTING CALCULATflRfi Raymond D. MacArthur, South Norwalk, Conn, assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed May 21, 1959, Ser. No. 814,893 10 Claims. (Cl. 101-95) This invention relates to new and useful improvements in calculators and has especial reference to means for the suppression of zeros to the left of the first significant digit in a number being printed.

The object of the invention is to provide a simple, efiicient, and economical device which employs a minimum number of parts.

In brief and general terms the invention includes the following elements,

(1) A type wheel to be moved to and from a platen;

(2) Means to so move the type wheel and nominated as a firing arm;

(3) Means engaging the firing arm to hold in a normal inoperative position, and nominated a scar;

(4) Means to restore the firing arm to normal position; 1

(5) Means to sequentially release the firing arm and then restore it;

(6) A rack slide having an upper edge formed at different levels;

(7) A latch for blocking movement of the firing arm and nominated a firing arm latch;

(8) Lip on the latch to be related to the rack slide edge to block or unblock the movement of the latch depending upon which level of the rack slide is beneath the lip;

(9) Springs associated with the various parts to restore them to normal position when released, and to operate them under certain conditions.

Generally speaking the firing arm is held in inoperative position by the sear but the sear is moved away from the firing arm by a stud on a rotating member at which time spring connected to the firing arm snaps it to operative position to move the type wheel to printing position. Immediately thereafter another stud on the rotating member will engage the restoring arm to move the firing arm to normal position and a spring connected to the sear will move it into position to re-engage the firing arm to hold it in inoperative position.

When the rack slide is in zero position the lower level thereon is beneath the lip on the latch arm so that the latch arm can pivot and move into position to block the firing arm under the influence of a spring but when the rack slide is in any position higher than zero the upper level of the slide is beneath the lip and prevents the latch from being pivoted.

Thus it is seen that when the rack slide is in one position, means thereon will block the movement of the latch arm and when it is in another position the latch arm is not blocked and can be moved.

The present preferred form which the invention may assume is illustrated in the drawings, of which:

FIG. 1 is a partial fragmentary front to rear vertical section showing the parts in positions of rest;

FIG. 2 is an enlarged similar view showing the parts in the position when the printing of a zero is being suppressed; and,

FIG. 3 is an enlarged similar view showing the parts in the position when a number higher than Zero is being printed.

This invention is shown in the drawings as applied to a machine in which there is a platen 10, a printing wheel 11, mounted on one end of a bell crank 12, which is 3,1353% Patented Dec. 31, 1963 pivotally mounted on a shaft 13, the lower end of the bell crank being engaged in any suitable manner with the upper end of a firing arm 14, pivotally mounted on a shaft 15, and normally urged in a counterclockwise direction by a spring 16. When the firing arm is moved counterclockwise, it swings the bell crank 12 in a clockwise direction to advance the printing wheel 11 to the printing position shown in FIG. 3.

The printing wheel 11 is rotated to present the desired character in printing position by means of its engagement with a gear 17 the teeth of which engage with rack teeth 18 on the upper limb 19 of a rack slide generally indicated by the numeral 20. This machine is of the type which has a pin box for setting up selected numbers, and when a number has been entered and the add bar is depressed the rack 21) moves rearwardly in the well known manner to turn the type wheel by the desired amount. The pin box and the add bar are not shown since they are well known and form no part of the invention. When a number containing several digits has been entered and the racks are advanced, it is desired not to print zeros to the left of the first significant digit. To achieve this end the following improved mechanism, which constitutes the invention has been derived.

The rack slide 26 is provided with a lower limb 21 which is connected to the upper limb 19 by a vertical limb 22, so that two limbs 19 and 21 move together when the rack is advanced. The major portion of the lower limb 21 of the rack 21) provides an upper level denoted as 23, but at the rear portion thereof adjacent the vertical limb 22 it provides a lower level denoted as 24. The purpose of these different levels will be soon explained.

The firing arm 14 at its lower portion to the right of the shaft 15 has an extension 25 on the end of which is a cut-away portion to form a shoulder 26. At the lower left portion of this arm 14- there is a cut-away portion to form a shoulder 27. To the left of the central portion of arm 14 is an extending lip 28.

In the normal at rest position of the parts as shown in FIG. 3, the shoulder 26 is engaged by a laterally extending lip 29 at the upper end of a firing arm sear 3t) pivoted on shaft 31. On this sear is a stud 32 to which is connected one end of a spring 33. This spring tends to move the sear 30 in a counterclockwise direction. Also pivoted on the shaft 31 is a firing arm latch 34 one end of which has a horizontal laterally extending lip 35 which is in a plane to lie over the upper edge or level 23 of the lower limb 21 of the rack slide Ztl. The other end of the latch is turned over to form a flange 36 which, in a certain position, FIG. 2, of the latch 34 is adapted to be nested in the cut-away portion against the shoulder 27 on the lower end of the firing arm 14 to block counterclockwise motion of said firing arm. The sear 30 is provided with a stud 37 which extends laterally from the sear and is in position to lie over the upper edge of the latch 34-. In the position of the sear 31 shown in FIG. 1 this stud lies closely above the edge of the latch so that the latch cannot be moved clockwise but when the sear 30 is released to the position shown in FIG. 2, the stud has been moved up so that there is room for the latch to be so moved. A spring 38 extends from the stud 32 on the sear 30 to the latch 34 and tends to move the latch clockwise when the sear 30 is moved clockwise.

On a shaft 39 there is a cycling disk 39 which rotates counterclockwise as shown by the arrow. On one side of this disk is a stud 40 and on the other side is a stud 41. The position of stud 40 is in advance of that of stud 41 as will be seen.

Pivoted on the shaft 15 is a restoring arm 42 one end of which has an extending finger 43 and the other end has a flange 44 to which one end of the spring 33 is connected. On the restoring arm 42 is a stud 45 which,

when the arm 4-2 is moved clockwise from the position shown in FIG. 1 will engage the lip 28 on the firing arm 14- to move said firing arm in a clockwise direction to withdraw the printing wheel 11 from the printing position.

Each latch 34 is provided with an car as (FIG. 2) positioned under the corresponding car as (not shown) in the next adjacent lower order.

Operation of the Mechanism When the shaft 39 is rotated it will turn the disk 39' and bring the stud 4t) into contact with the lip 29 on the sear 36 thus turning the sear 3t} clockwise from the position shown in FIG. 1 to that shown in FIG. 2. This will release the firing arm 14 to allow the spring 16 to move said arm counterclockwise to the position shown in FIG. 3 and snap the printing wheel to impact position, as shown in FIG. 3. In the position of the parts as shown in FIG. 1, this impact will be permitted because the lower limb 21 of the rack slide is advanced beyond the at rest and the zero position so that the upper edge 23 lies under the lip 35 of the latch arm 34 so that latch arm cannot be moved up by the spring 38.

After impact the printing wheel 11 is immediately returned to the position of rest shown in FIG. 1 by the following means: The stud 41 on the disk 39 contacts the finger 43 on the restoring arm 42 and moves said arm clockwise to move the stud 45 thereon up against the lip 28 on the firing arm 14 to snap the arm 14 in a clockwise direction. Tln's movement not only retracts the printing wheel but also lowers the shoulder 26 on the firing arm so that the spring 33 can pull the lip 29 on the sear 3i} forward over the shoulder 26 to hold the firing arm in the position shown in MG. 1, which in its at rest position. As the sear 3%) thus moves counterclockwise the stud 37 thereon moves down to lie close to the upper edge of the latch arm 34. The above operation is predicated on the movement of the rack slide to a position representing a numeral from one or more. However, if the rack slide moves to the zero position as shown in FIG. 2 then it is to be noted that the lip 35 on the latch arm 34 lies over the lower level 24 on the lower limb 21 of the rack slide. Thus it will be seen that as soon as the sear 30 starts to be moved clockwise the stud 37 thereon moves up from close adjacency to the upper edge of the latch arm 34 and allows the spring 33 to pull the latch arm clockwise to bring the flange 36 to lie closely adjacent the shoulder 27 of the firing arm 14 and thus prevent the firing arm from being turned counterclockwise to move the printing wheel to impact position. This blocking position is shown in FIG. 2. The latch arm 34 can thus be moved because the lip 35 thereon is able to move down. The parts are restored from this position in the same manner as before described.

When a rack slide in any order other than the units order has advanced beyond the at rest and the zero position (FIG. 3) its respective latch arm 34 is restrained in its unblocking position as previously explained. The car do of said latch arm is also restrained. The coaction of this ear with the latch arm ears in all the lower orders will maintain the lower order latch arms in unblocking position. This will allow all the lower order firing arms to print even if their respective rack slides are still in zero position.

While I have described what I consider to be a highly desirable embodiment of my invention, it is obvious that many changes in form could be made without departing from the invention and I, therefore, do not limit myself to the exact form herein shown and described, nor to anything less than the whole of my invention as hereinbefore set forth, and as hereinafter claimed.

What I claim is:

l. A printing mechanism of the class described having a character bearing element movable from a non-printing position to a printing position, drive means, and settable stop means, comprising a displaceable rack driven by the drive means and arrested by engagement with the settable stop means, moving means operable to move said character bearing element from the non-printing to printing position, a latch member engaging said moving means in a first position of said displaceable rack to render the moving means inoperable whereby the character bearing element remains in the non-printing position, said latch member further engaging said displ-aceable rack in a second position of said displaceable rack to render the moving means operable, whereby the character bearing element is moved from non-printing position to printing position, and resetting means to reset the moving means and thereby the character bearing element.

2. A printing mechanism of the class described having a character bearing element movable from a non-printing to a printing position, drive means, and settable stop means, comprising a displaceable rack driven by said drive means and arrested by said settable stop means, moving means including a firing arm operable to move said print wheel from non-printing position to printing position, a latch member engageable with either said firing arm or said displaceable rack, said latch member engaging said firing arm in a first position of said displaceable rack whereby the moving means is rendered inoperable and said character bearing element remains in nonprinting position, said latch member further engaging said displaceable rack in a second position of said displaceable rack whereby said moving means is operable to move said character bearing element from non-printing position to printing position, and resetting means to reset the moving means and thereby the character hearing element.

3. The invention of claim 2 in which said moving means comprises a bell crank adapted for rocking by said firing arm for moving the character bearing element, said firing arm being movable from an unfired position to a fired position whereby the character bearing element is rocked by the bell crank from its non-printing position to its printing position, a spring urging said firing arm to its fired position, a sear normally engaged with said firing arm to restrain it in unfired position against the urging of the spring, a lug on said sear engaging the latch member to prevent movement of said latch member and release means to move said sear out of engagement with said firing arm and latch member, whereby said firing arm is movable to its fired position and said latch member is movable to either of its engaging positions, the resetting means coacting with said firing arm and sear to reengage them.

4. The invention of claim 2 in which said character bearing element, drive means, settable stop means, displaceable rack, moving means, latch member, and resetting means comprise an ordinal set, additional like ordinal sets positioned side by side to form a series of orders, an car on the latch member of each ordinal set, said ear coacting with the car on the latch member in the adjacent lower ordinal set whereby displacement of a higher order rack to its second position the coacting ears prevent any lower order latch members from engaging the firing arms of their respective lower order moving means.

5. The invention of claim 4 in which said first position of the displaceab le rack is its zero position.

6. The invention of claim 2 in which said displaceable rack is longitudinally displaceable and has upper and lower spaced horizontal members and a vertical member connecting said horizontal members for unitary motion, a recessed portion on said lower member, a lip on said latch member movable into said recessed portion in the first position of said displaceable rack whereby said latch member engages the firing arm to render the moving means inoperable and said lip contacting the non-recessed portion of the lower member in the second position of the displaceable rack whereby the moving means is operable.

7. The invention of claim 6 in which said moving means, latch member, and resetting means are located in the space between the upper and lower horizontal members and in which the recess on the lower horizontal member is on the side facing the upper horizontal member.

8. A printing calculator of the class described having a single ordinal position, a print Wheel, a printing platen, rack drive means, and settable rack stop means, comprising a longitudinally displaceable print wheel positioning rack driven by said rack drive means and arrested directly by said settable rack stop means, said longitudinally displaceable rack having upper and lower spaced horizontal members and a vertical member connecting said horizontal members for unitary motion, a bell cra-nk for rocking said print wheel from printing to non-printing position, a firing arm connected to said bell crank for controlling the motion thereof, -a spring urging said firing arm and bell crank to printing position, a sear normally in engagement with said firing arm to prevent it from moving to printing position, a latch member adapted to be engaged with said firing arm to maintain it in non-printing position, a lug on said sear engaging said latch member to normally maintain it out of contact with said firing arm, a spring urging said latch member against said lug and towards a position of engagement with said firing arm, said firing arm, scar and latch member mounted in the space between the upper and lower horizontal rack members, a recess on the lower horizontal rack member facing the upper horizontal rack member, a lip on said latch member normally positioned over said recess and movable in said recess to allow said latch member to assume a firing arm latching position, and which when the rack has been displaced engages the non-recessed portion of said lower horizontal member to maintain said latch member in unlatching position, a cycling disk rotatably mounted in said space between the upper and lower horizontal members, a first lug on said cycling disk adapted to displace the sear from engagement with the firing arm upon rotation of the cycling disk, a resetting mechanism adapted to reset all firing arms and a second lug on said cycling disk to operate said reset mechanism upon further rotation of said cyling disk.

9. The invent-ion of claim 8 including plural ordinal positions, an ear on the latch member of each ordinal set, said ear coacting with the ear on the latch member in the next lower ordinal position, whereby displacement of a higher order rack to a position wherein its non-recessed portion coacts with its latch member to maintain the blocking member in unlatching position maintains all lower order latching members in unblooking position whether or not the lower order racks have been displaced.

10. The invention of claim 9 in which said recessed portion is positioned under the latch ear when the rack is in its zero position.

References Cited in the file of this patent UNITED STATES PATENTS 2,199,561 Fuller et al. May 7, 1940 2,227,143 Knutsen Dec. 31, 1940 2,297,803 Scheerer et al. Oct. 6, 1942 2,506,337 Boyden May 2, 1950 2,720,832 Luning Oct. 18, 1955 2,800,074 Busch July 23, 1957 2,879,712 Mark Mar. 81, 1959 2,894,449 Boyden -2 July 14, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,115,828 December 31, 1963 Raymond D. MacArthur It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 4, for "engaging" read obstructing line 20, for "print wheel" read character bearing element same column 4, lines 33 to 49, strike out the present claim 3, and insert instead:

3., A printing mechanism of the class described having a character bearing element movable from a nonprinting to a printing position, drive means, and settable stop means, comprising a displaceable rack driven by said drive means and arrested by said settable stop means, moving means including a firing arm and a bellcrank, said firing arm being movable from an unfired position to a fired position to rock the bell-crank and thereby the character bearing element from its non print' ing position to its printing position, a spring urging said firing arm to its fired position, a sear normally engaged with said firing arm to restrain it in unfired position against the urging of said spring, a latch member engageable with either said firing arm or said displaceable rack, a lug on said sear engaging the latch member to prevent movement of said latch member, release means to move said sear out of engagement with said firing arm and latch member, said latch member when released engaging said firing arm in a first position of said displaceable rack to render the moving means inoperable to move said character bearing element from non-printing position to printing position, said latch member when released engaging said displaceable rack in a second position of said displaceable rack to render said moving means operable to move said character bearing element from non-printing position to printing position, and resetting means to reset the moving means and there--' by the character bearing element, said resetting means also coacting with the firing arm and sear to reengage them.

lines 50 to 60, strike out the present claim 4, and insert instead:

4, A printing mechanism of the class described having a character bearing element movable from a n-onprinting to a printing position, drive means, and settable stop means, comprising a displaceable rack driven by said drive means and arrested by said settable stop means, moving means including a firin g arm operable to move said character bearing element from nonprinting position to printing position, a latch member engageable with either said firing arm of said displaceable rack, said latch member engaging said firing arm in a first position of said displaceable rack whereby the moving means is rendered inoperable and said character bearing element remains in non-printing position, said latch member further engaging said displaceable rack in a second position of said displaceable rack whereby said moving means is operable to move said character bearing element from non-printing position to printing position, resetting means to reset the'moving means and thereby the character bearing element, said character bearing element, drive means, csettable stop means, displaceable rack, moving means, latch member, and resetting means comprising an ordinal set, additional like ordinal sets positioned side by side to form a series of orders and an ear on the latch member of each ordinal set, said ear coacting with the ear on the latch member in the adjacent lower ordinal set whereby the coacting ears in the displacement of a higher order rack to its second position prevent any lower order latch members from engaging the firing arms of their respective lower order moving means.

lines 63 to 73, strike out the present claim 6, and insert instead:

6. A printing mechanism of the class described having a character bearing element movable from a nbnprinting to a printing position, drive means, and set table stop means, comprising a longitudinally displace?- able rack driven by said drive means and arrested by said S'ettable stop means, said longitudinally displaceable rack having upper and lower spaced horizontal members and a vertical member connecting said horizontal members for unitary motion, a recessed portion on said lower member, moving means including a firing arm operable to move said character bearing element from non-printing position to printing position, a latch member engageable with eithersaidlfiring arm or said displaceable rack, a lip on said latch member moveavle into the recessed portion on said lower member permitting said latch member to engage said firing arm in a first position of said displaceable rack whereby the moving means is rendered inoperablea-nd-- said character bearing element remains in now-printingv posi tion, said lip on said latch member further engaging said non-re cessed portion of said displaceable rack in a second position of said displaceabl'e "rack whereby said moving means is operable to move said character bearing element from non-printing position to printing position, and resetting means to reset the moving means and thereby the character bearing element.

Signed and sealed this 14th day of July 1964.

(SEAL) Attest:

ESTON G. JOHNSON EDWARD J, BRENNER Attesting Officer Commissioner of Patents 

1. A PRINTING MECHANISM OF THE CLASS DESCRIBED HAVING A CHARACTER BEARING ELEMENT MOVABLE FROM A NON-PRINTING POSITION TO A PRINTING POSITION, DRIVE MEANS, AND SETTABLE STOP MEANS, COMPRISING A DISPLACEABLE RACK DRIVEN BY THE DRIVE MEANS AND ARRESTED BY ENGAGEMENT WITH THE SETTABLE STOP MEANS, MOVING MEANS OPERABLE TO MOVE SAID CHARACTER BEARING ELEMENT FROM THE NON-PRINTING TO PRINTING POSITION, A LATCH MEMBER ENGAGING SAID MOVING MEANS IN A FIRST POSITION OF SAID DISPLACEABLE RACK TO RENDER THE MOVING MEANS INOPERABLE WHEREBY THE CHARACTER BEARING ELEMENT REMAINS IN THE NON-PRINTING POSITION, SAID LATCH MEMBER FURTHER ENGAGING SAID DISPLACEABLE RACK IN A SECOND POSITION OF SAID DISPLACEABLE RACK TO RENDER THE MOVING MEANS OPERABLE, WHEREBY THE CHARACTER BEARING ELEMENT IS MOVED FROM NON-PRINTING POSITION TO PRINTING POSITION, AND RESETTING MEANS TO RESET THE MOVING MEANS AND THEREBY THE CHARACTER BEARING ELEMENT. 